阅读理解

　　If you’re training for a marathon, a proper plan for water intake(摄入)is important．Of course, there’s the risk of dehydration(脱水)．But athletes now know they can also get into trouble by drinking to much．To much water intake can lower levels of sodium(钠)in the blood．The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research．

　　Experts advise long distance runners to replace the liquids they sweat out．Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight．

　　One technique for deciding how much water you need is to get the exact numbers．Runners have to weight themselves before and after a run to determine how much water they’ve lost．If their weight drops by more than 2 percent, they have not drunk enough water．

　　Hyponatremia occurs when runners drink so much water that blood salt levels drop off．A study published last year tested 488 runners who completed the Boston Marathon and found 13 percent of them had dangerously low blood salt levels．The first sign that runners may notice is slightly swelling in the hands．They can’t get their rings off, and then they might feel sick．They may not remember where they are．In fact, most runners get enough salt to get back to normal levels by eating just one meal after a run．Contrary to the old advice that runners should drink as much as they can to prevent dehydration, the new research has shown that the body is a remarkable machine that actually tells you via thirst when you need water．

完形填空

　　A man hired a taxi outside the airfield．The cab had a woolen carpet with brilliant silk edges．On the glass partition(隔板)behind the driver's seat．　　1　　 a wonderful painting．Its windows were all 　　2　　．The customer was very much 　　3　　 and said to the driver, “I've never seen a nicer cab．”“Thank you for your praise, ”the driver answered 　　4　　．

　　“How did it occur to you to 　　5　　 your ca r?” asked tile customer·

“The car isn't mine．”said the driver．“It belongs to the company．I used to be a 　　6　　 of cabs．When they returned, all of them were as 　　7　　 as garbage calls with cigarette ends and 　　8　　 scattered(散乱)here and there．On the seats or door-handles could be found something 　　9　　 like chewing gum．Why so? I thought if the car itself were very clean, the passengers would　most likely be 　　10　　．and avoid littering．”

　　“When I got a 　　11　　 to be a taxi driver, I began to put my idea into 　　12　　 to tidy and decorate the car．Now 　　13　　．a new passenger get on my car, I would make a 　　14　　 and be sure it is in good order．When my car returned after a day's work, it always remains 　　15　　．”

　　When doing a thing．one makes efforts and wants to see the 　　16　　．To change others one has to make twice the 　　17　　 but get half the result．To change oneself is tile other way round－more fruit with less effort．One had better ask oneself why one makes 　　18　　 on others much more than oneself．If you take enough 　　19　　 to do as best as you can for other people's sake, your efforts will naturally 　　20　　．